What security feature must Dynatrace Managed customers configure themselves?

The correct answer emphasizes the importance of hard disk encryption as a security feature that Dynatrace Managed customers must configure on their own. Hard disk encryption protects sensitive data stored on the disks of the Dynatrace Managed cluster. This is crucial for ensuring that unauthorized users cannot access any data during a security breach. Since Dynatrace Managed is typically deployed in a customer's environment, the responsibility for data security measures such as encryption falls on the customer to ensure compliance with their specific security policies and standards.

Customers must implement hard disk encryption practices to protect data at rest, thereby preventing potential threats that could arise from physical access to the storage devices. This self-managed aspect of security is pivotal because it grants customers the flexibility to choose the encryption standards and methods that best fit their organization's requirements, allowing for customization based on the sensitivity of the data being handled.

Other security features, while also important, are either not under the direct control of the user in the same way, not a primary concern for the deployment of Dynatrace Managed, or they might be managed within the broader infrastructure rather than specifically by Dynatrace itself.